This epidemiologic study seeks to identify host and environmental factors of 50,000 former college students from Harvard and the University of Pennsylvania that predispose to specific chronic diseases later in life. In Phase I of the study, physical examination and other college records, 1916-1950, provide the predictor characteristics being examined for associations with subsequent nonfatal and fatal diseases measured through self-administered mail questionnaires (1962, 1966, 1972, 1976, 1977, and 1978) and death certificates that are kept current. In Phase II of the study, contemporary, or alumni characteristics, including physical activity patterns, social habits, and health status assessed through the above cited questionnaires are being examined in relation to heart attacks and other chronic diseases. With these two levels of information (Phases I an II) we are determining if certain familial attributes or youth experiences are as influential as later predictors of specific diseases.